Arrangement for detachably securing a grinding wheel or a group of grinding wheels on a wheel spindle

ABSTRACT

Arrangement for releasably fastening a grinding wheel or a group of grinding wheels on a wheel spindle, for example, a group of grinding wheels in a spectacle-lens-edging machine. The machine has a grinding-wheel-retaining shaft that is arranged, in an axially displaceable manner, in a coaxial bore of the wheel spindle, a retaining disk that may be fastened in a releasable manner at the free end of the grinding-wheel-retaining shaft, and clamping elements arranged between the wheel spindle and the grinding-wheel-retaining shaft for axially bracing and releasing the grinding wheel or the group of grinding wheels between the wheel spindle and the retaining disk.

FIELD OF THE INVENTION

The invention relates to an arrangement for releasably securing agrinding wheel or a group of grinding wheels on a wheel spindle, forexample, a wheel spindle in a spectacle-lens-edging machine, as referredto in commonly owned German Published Patent Application No. 195 27 222.

BACKGROUND INFORMATION

Grinding wheels or groups of grinding wheels may be releaseably securedon a wheel spindle to permit them to be exchanged if, for example, theybecome worn or if, in respect of different machining operations, theyare to be exchanged.

Grinding wheels for spectacle-lens-edging machines may be provided witha cylindrical region and a grooved region. The cylindrical region may beused to pre-machine a spectacle lens to shape and the grooved region maybe used to form a bevel on the circumference of the shaped spectaclelens. More than one grinding wheel may be used, for example, threegrinding wheels, of which one grinding wheel may be provided formachining plastic lenses, a cylindrical grinding wheel may be providedfor the rough grinding of spectacle lenses made of silicate glass and agrinding wheel with a bevel groove may be provided for precision or finemachining and beveling.

The wheel spindle and the grinding wheels are arranged on thespectacle-lens-edging machine in a grinding chamber, which may be closedon all sides to prevent abraded material produced during grinding and acooling lubricant from passing to the outside. The cooling lubricant maybe sprayed into the grinding region between the grinding wheel and thespectacle lens. Although the grinding chamber is kept as small aspossible, a spray guard may be arranged tightly around the grindingwheels, said spray guard only leaving the grinding region exposed andhaving contact shoe regions, on which the unmachined lens and/or theground-to-shape spectacle lens is positioned to be measured.

The grinding chamber may define a confined space, which may make it verydifficult to exchange grinding wheels or groups of grinding wheels,since the grinding wheels are connected to the wheel spindle such that agrinding-wheel-retaining shaft, which is connected integrally to thewheel spindle and has a smaller diameter than the wheel spindle, has asleeve having a length smaller than the width of the grinding wheel(s).The sleeve bears the grinding wheels and centers them, while a retainingdisk braces the wheel spindle, the retaining disk having a greaterdiameter than the diameter of the sleeve. The retaining disk may bescrewed to the grinding-wheel-retaining shaft to brace the grindingwheel with the wheel spindle.

To remove the grinding wheels, the grinding chamber must have enoughspace sufficient to permit the grinding wheels to be withdrawn from thegrinding-wheel-retaining shaft and the grinding chamber, individually ortogether.

Furthermore, the grinding chamber must have enough space sufficient topermit a suitable wrench to attach to a screw connection of theretaining disk to clamp and release the connection. Finally, a doubletolerance is provided between the grinding-wheel-retaining shaft and thesleeve and the sleeve and the grinding wheel or the group of grindingwheels, said double tolerance adversely affecting the concentric-runningproperties.

If the initially mentioned spray guard with the contact shoes ispresent, the guard may need to be removed before the grinding wheel(s)is removed.

In the case of prior art spectacle-lens-edging machines, the task ofexchanging a grinding wheel or a group of grinding wheels is thustime-intensive and requires a certain amount of skill.

SUMMARY OF THE INVENTION

An object of the present invention is to facilitate the installation andthe removal of grinding wheels or groups of grinding wheels on wheelspindles with confined space conditions in the axial direction. Anotherobject of the present invention is to help ensure improvedconcentric-running properties.

In one exemplary embodiment according to the present invention, anarrangement is provided to releasably secure a grinding wheel or a groupof grinding wheels on a wheel spindle, for example, on a wheel spindleof a spectacle-lens-edging machine. The grinding-wheel-retaining shaftis arranged in an axially displaceable manner in a coaxial bore of thewheel spindle with a close fit. The grinding-wheel-retaining shaft maybe retracted into the wheel spindle by at least the width of a grindingwheel, on which a grinding wheel(s) is seated directly and without play.The free end of the grinding-wheel-retaining shaft may be provided witha retaining disk to secure clamping elements between the wheel spindleand the grinding-wheel-retaining shaft in a releasable manner. Thishelps ensure the axial bracing and release of the grinding wheel(s)between the wheel spindle and the retaining disk and also the retractionof the grinding-wheel-retaining shaft into the wheel spindle by at leastthe width of a grinding wheel.

In accordance with another exemplary embodiment of the presentinvention, the grinding wheel(s) is seated directly and without play onthe grinding-wheel-retaining shaft, without the prior-art doubletolerance being provided between the grinding-wheel-retaining shaft andthe sleeve.

To exchange a grinding wheel or a group of grinding wheels, thegrinding-wheel-retaining shaft is displaced in the direction of thegrinding wheel(s) to release the bracing of the grinding wheel(s)between the wheel spindle and the retaining disk. In this manner, theretaining disk may be removed from the grinding-wheel-retaining shaftwithout the aid of a tool. Thereafter, the grinding-wheel-retainingshaft is displaced in the opposite direction within the wheel spindle sothat its free end completely frees the grinding wheel, or at least onegrinding wheel of a group of grinding wheels. In this manner, thegrinding wheel(s) may be removed from the grinding chamber without axialdisplacement from the region of the wheel spindle. To insert a grindingwheel(s), the procedure described above may be performed in reverse. Thenew grinding wheel(s) is positioned in the region of the wheel spindlein the grinding chamber when the grinding-wheel-retaining shaft has beenretracted. Then, the grinding-wheel-retaining shaft is extended out ofthe wheel spindle, and guided through the accommodating bore in thegrinding wheel(s). Next, the retaining disk is secured to the free endof the grinding-wheel-retaining shaft. Then, thegrinding-wheel-retaining shaft is moved in the opposite direction tobrace the grinding wheel or the group of grinding wheels between thewheel spindle and the retaining disk.

The retaining disk may be screwed to the free end of thegrinding-wheel-retaining shaft, for example, using a through-bolt orthreaded pin connected to the retaining disk. In this manner, a specialtool would not be required to release the screw connection because thebracing of the grinding wheel(s) between the wheel spindle and theretaining disk occurs by axial displacement of thegrinding-wheel-retaining shaft, and the screw connection of theretaining disk may be rotated freely once the bracing has beeneliminated.

In accordance with another exemplary embodiment of the presentinvention, the retaining disk is connected to the free end of thegrinding-wheel-retaining shaft as a bayonet connection. In this manner,the retaining disk may be released from the grinding-wheel-retainingshaft without the aid of a tool, release not being possible in thebraced state.

The clamping elements between the wheel spindle and thegrinding-wheel-retaining shaft may comprise a threaded connectionbetween the grinding-wheel-retaining shaft and the wheel spindle. Forthis purpose, the externally threaded grinding-wheel-retaining shaft maybe screwed directly into a threaded bore in the wheel spindle.Alternatively, the grinding-wheel-retaining shaft may be provided with athreaded bore for a headed bolt, which may be supported on the wheelspindle via a flanged bushing.

The grinding-wheel-retaining shaft screwed into the wheel spindle may bemanually rotated in the bore of the wheel spindle using a suitablehandle. A tool may be provided to tighten the handle. For example, if aheaded bolt is used to displace and brace the grinding-wheel-retainingshaft, a hexagon-socket wrench may be used.

To speed up the screwing and unscrewing of the grinding-wheel-retainingshaft in the bore of the wheel spindle or the headed bolt, and to beable to dispense with clamping tools, for example, an electric rotarydrive may be arranged between the wheel spindle and thegrinding-wheel-retaining shaft or the headed bolt.

A hydraulic or pneumatic piston/cylinder unit may be provided as aclamping element between the grinding-wheel-retaining shaft and thewheel spindle, said unit providing the bracing and allowing the quickaxial displacement of the grinding-wheel-retaining shaft in the bore ofthe wheel spindle. This arrangement permits a quick actuation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows part of a spectacle-lens-edging machine in cross section,with a group of grinding wheels on a wheel spindle;

FIG. 2 is a view similar to FIG. 1 of a further embodiment; and

FIG. 3 is a view as in FIG. 1 of another embodiment.

DETAILED DESCRIPTION

Of the spectacle-lens-edging machine, only a housing neck 8, in which awheel spindle 9 is mounted by means of a pair of rolling-contactbearings 10, is illustrated.

A group of grinding wheels, comprising a grinding wheel 1 for plastic,with a metal ring 2 in which diamond abrasive materials have beenmetalically bound, a rough-grinding wheel for silicate glass, with ametal ring 4 in which diamond abrasive materials have been metalicallybound, and a precision-grinding wheel 5, with a ring 6 which is of thesame design and has a bevel groove 7 for forming a ridge bevel on thecircumference of a ground-to-shape spectacle lens, are seated on agrinding-wheel-retaining shaft 13, which has been introduced with aclose fit into a bore 11 of the wheel spindle 9. Thegrinding-wheel-retaining shaft 13 has a threaded bore 14 and acylindrical bore 15, which is coaxial with the threaded bore and has alarger diameter. At the free end, diametrically opposite, angled slots16 for a bayonet securing arrangement (described below) are provided inthe grinding-wheel-retaining shaft 13.

A headed bolt 17 with a hexagon-socket head 18 is screwed into thethreaded bore 14. The head 18 is supported on the wheel spindle 9 by aflanged bushing 19, the flanged bushing 19 being adhesively bondedwithin the wheel spindle 9.

To brace the group of grinding wheels 1, 3, 5 with the wheel spindle 9,a retaining disk 20 is inserted into the bore 15 via cylindricalextension 21, on which radial studs 22 are located, such that the radialstuds 22 and the cylindrical extension 21 pass into the angled slots 16and, by virtue of rotation, form the bayonet connection. A compressionspring 23 is supported between the cylindrical extension 21 and ashoulder at the end of the bore 15 in the grinding-wheel-retaining shaft13. If the headed bolt 17 is then rotated to retract thegrinding-wheel-retaining shaft 13 into the bore 11 of the wheel spindle9, the retaining disk 20 abuts against the group of grinding wheels 1,3, 5 and braces the grinding wheels 1, 3, 5 with the wheel spindle 9 viaa supporting disk 12.

To release the group of grinding wheels 1, 3, 5, the headed bolt 17 isrotated in the opposite direction until it reaches the positionillustrated in the figure. The retaining disk 20 may then be easilyremoved. If the headed bolt 17 is rotated again in the direction forclamping, the grinding-wheel-retaining shaft 13 is retracted into thewheel spindle 9 so that the end of the grinding-wheel-retaining shaft 13is guided out of the accommodating bore of the grinding wheel 5. In thismanner, the group of grinding wheels 1, 3, 5 may be removed radiallyfrom the region of the grinding-wheel-retaining shaft 13.

The grinding-wheel-retaining shaft 13 may also be retracted into thewheel spindle 9 so that the entire group of grinding wheels 1, 3, 5 maybe removed in the radial direction.

The procedure may be performed in reverse to insert a group of grindingwheels 1, 3, 5.

Instead of using a headed bolt 17 in the bore 11 of the wheel spindle 9to move the grinding-wheel-retaining shaft 13, thegrinding-wheel-retaining shaft 13 may be screwed directly into acorresponding threaded bore of the wheel spindle 9. In this manner, thegrinding-wheel-retaining shaft 13 may be, for example, guided out of thewheel spindle 9 and into the region of the flanged bushing 19, which isillustrated with headed bolt 17. The grinding-wheel-retaining shaft 13may be provided with a handwheel to rotate the grinding-wheel-retainingshaft 13 in the wheel spindle 9.

As shown in FIG. 2, the retaining disk 20 a can be mounted by a threadedpin 21 a that is threaded into the threaded bore 14.

To speed up the exchanging of a group of grinding wheels 1, 3, 5 or asingle grinding wheel, the headed bolt 17 may include a threadedspindle, which may be rotated by an electromotive drive. A similar drivemay also be provided if the grinding-wheel-retaining shaft 13 is screweddirectly into the wheel spindle 9.

Furthermore, as shown in FIG. 3, a hydraulic or pneumaticpiston/cylinder unit 24 may be arranged between the wheel spindle 9 andthe grinding-wheel-retaining shaft 13. The unit 24 has a connection 26for pressurized fluid. Also, cup springs 25 are arranged between theshaft 13 and the piston head. The unit 24 may permit the quickdisplacement of the grinding-wheel-retaining shaft 13 in relation to thewheel spindle 9 and may provide the bracing of the grinding wheels 1, 3,5.

1. Apparatus for releasably securing a grinding wheel or a group ofgrinding wheels in a spectacle-lens edging machine, comprising: a wheelspindle having an axis and a bore extending along the axis; agrinding-wheel-retaining shaft arranged with a close fit in the bore ofthe wheel spindle and being displaceable in the bore along the axis ofthe wheel spindle, the grinding wheel retaining shaft having a free endtoward a grinding wheel; at least one grinding wheel on the free end ofthe grinding-wheel-retaining shaft, the at least one grinding wheelhaving a width along the axis of the wheel spindle, thegrinding-wheel-retaining shaft being displaceable in the bore of thewheel spindle by at least the width of the grinding wheel; a retainingdisk releasably secured to the free end of the grinding-wheel-retainingshaft for retaining the at least one grinding wheel; and a clampingarrangement operable to axially release and retract thegrinding-wheel-retaining shaft into the bore of the wheel spindle by atleast the width of the at least one grinding wheel; wherein displacementof the grinding-wheel-retaining shaft into the bore of the wheel spindlein one axial direction axially braces the at least one grinding wheelbetween the wheel spindle and the retaining disk, and in an oppositeaxial direction releases the retaining disk from the wheel spindle andwherein displacement of the grinding-wheel-retaining shaft into the boreof the wheel spindle in said one axial direction by at least the widthof the at least one grinding wheel releases said at least one grindingwheel from the grinding-wheel-retaining shaft.
 2. The apparatus of claim1, wherein the retaining disk is configured to be screwed to the freeend of the grinding-wheel-retaining shaft.
 3. The apparatus of claim 1,wherein the retaining disk includes an extension to provide a bayonetconnection with the free distal end of the grinding-wheel-retainingshaft.
 4. The apparatus of claim 1, further comprising a screwconnection in the bore between the grinding-wheel-retaining shaft andthe wheel spindle, wherein the grinding-wheel-retaining shaft isdisplaceable along the axis of the wheel spindle via the screwconnection.
 5. The apparatus of claim 4, wherein the clampingarrangement includes a headed bolt and a flanged bushing to support theheaded bolt on the wheel spindle, the grinding-wheel-retaining shaftincluding a threaded bore to receive the headed bolt.
 6. The apparatusof claim 1, wherein the clamping arrangement includes at least one of ahydraulic and pneumatic piston/cylinder unit to displace thegrinding-wheel-retaining shaft along the bore of the wheel spindle.